A photovoltaic system comprises a plurality of solar cells and one or more photovoltaic inverters. The solar cells convert solar radiation to direct current, which is converted by a photovoltaic inverter to alternating current. A photovoltaic string comprises a set of solar cells that are electrically connected in series. Two or more photovoltaic strings may be further electrically connected in series for increased current output. For example, a photovoltaic module may comprise one or more series-connected photovoltaic strings that are packaged on the same frame. A photovoltaic module may be electrically connected in series and/or electrically connected in parallel with other photovoltaic modules.
The performance of a photovoltaic string may be degraded because of shading, presence of dirt, electrical malfunction, and other degradations. A degraded photovoltaic string may have reduced power output, which may adversely affect the power output of other photovoltaic strings that are electrically connected to the degraded photovoltaic string. Voltage clipping technology has been developed to limit the voltage of a photovoltaic string, thereby minimizing its impact to the rest of the photovoltaic system.